1. Field of the Invention
Knitting was an early invention of man. The earliest known knitted fabric is a pair of thick, handknitted wool socks found in an Egyptian tomb dating back to the 4th century B.C. Knitted fabrics are divided into two generaly types: (1) those produced by weft knitting, where one continuous yarn forms course across the fabric; and (2) those produced by warp knitting, where a series of yarns forms wales in the lengthwise direction of the fabric.
There are three fundamental stitches in weft knitting. They are (1) plain knit stitch, (2) purl stitch and (3) rib stitch. Rib-knit type fabrics have alternating lengthwise rows of plain and purl stitches constructed so that the face and back of the fabric appear alike. The double-knit stitch is a variation of the rib stitch.
Broadly defined, a double knit is a jersey construction knitted on a machine equipped with two sets of needles so that, in effect, the cloth is a "twice knitted" fabric in which, by the action of the double set of needles the two sides of the cloth are interlocked. The fabric resulting is heavier than a single-knit cloth. One side has a fine ribbed appearance and the reverse side the texture of a fine birdseye or diamond effect. The heavier, double knit construction makes the fabric more dimensionally stable than plain jersey and allows it to be cut without curling on the edges.
Double knit fabrics, particularly those made by a circular knitting method, had a tremendous growth in the apparel field. These fabrics are more pliable and elastic than fabrics constructed by other methods. Thus, they are especially adaptable for form-fitting garments such as hoisery, undergarments, foundation garments, sweaters, and sleepwear. They can be given durable creases for use in tailored suits, jackets and slacks. Fiber material used is most often wool, acetate, nylon, triacetate, acrylics, cotton, polyester and combinations thereof, but possibilities include all fibers and even paper yarns.
With advances in double knitting processes and machinery, the use of knitted fabrics in the apparel field became phenomenal. This exploding growth eventually led to excess capacity in the industry, which in turn fostered much poor quality goods and eventually the rejection of double knit fabric for many applications. The cessation in making many products out of this material resulted in very many double knit machines being idled. A large portion of these machines were purchased on extensive credit and their non-usage is a severe disadvantage to their owners. This invention relates to a way by which the marketability of double knits can be expanded considerably into non-apparel fields for making goods such as wall coverings, upholstery materials and draperies. These idled machines could thus be put back into operation.
In the case of double knit fabrics as well as in plain or single knit fabrics the outward exposed surface is generally called the "face" or "front" while the reverse side is designated the "back" or "back side". It is in this sense that these terms are employed in the description which follows.
2. Description of the Prior Art
In U.S. Pat. No. 3,616,146 there is proposed an adhesive sheet material in which the textile fabric carrier has been made hydrophobic and to which a continuous impermeable plastic resinous film is applied for minimizing stretch and fraying. A dried adhesive is applied over the coating capable of being activated by a liquid medium such as water or a solvent prior to use.
A wall covering is proposed in U.S. Pat. No. 3,962,510 having a long dimension and a short dimension and comprising a laminate of a facing material bonded to a woven fabric backing material. The backing material is woven with warp and filling yarns and each filling yarn comprises a percentage of thermoplastic fibers. The fibers remaining in each of the filling yarns and the warp yarns are not able to be autogenously bonded to the facing material. The warp yarns lie in the direction of the long dimension and the filling yarns are in the direction of the short dimension. Therefore, the wall covering is rendered more stiff and less flexible in the direction of its short dimension as compared to its long dimension.
U.S. Pat. No. 4,159,360 discloses stabilized fabrics which may be woven, knitted or tufted. The fabric layer is bonded to a stabilizing layer of staple or continuous filament fibers by an air-permeable bonding layer of thermoplastic material. Bonding is achieved by heat and pressure sufficient to melt the bonding layer and let it penetrate into the fibers of both the fabric and stabilizing layers.
In U.S. Pat. No. 2,813,052 there is disclosed a composite water-proof plasticized fabric and a method of making the same. It is especially addressed to knitted, netted or textile fabrics having substantial stretchability in all directions. U.S. Pat. No. 3,440,133 discloses a coated, knitted fabric that has a relatively high ratio of percentage stretch in its wales direction to its courses direction. Such fabric is said to be particularly useful as a covering material in the upholstery industry.
It is suggested in the prior patented art that by coating or impregnation of knitted as well as woven textile fabrics these can be dimensionally stabilized sufficiently to enable their utilization as wall coverings and/or upholstery materials. Such treated materials have been commercially successful only in the case of woven fabrics which are being utilized fairly extensively in upholsery and to a lesser extent as wall coverings. Knit fabrics, because of their high degree of stretch, pliability, susceptibility to distortion of the pattern of the courses and/or wales of the knit yarns, even when coated, impregnated or otherwise treated by hitherto known methods, could not be successfully stabilized to enable their practical use as wall coverings and upholsering fabrics. By treatment of the knitted fabric with a sufficiently large amount of coating material to stabilize the fabric, the material becomes too stiff for practical handling. Lesser amounts of coating composition applied to the fabric does not provide the desired degree of stabilization.